Remove WP_CLI from the dynamicConstantNames list

[IanDelMar]

This PR removes the WP_CLI constant from the dynamicConstantNames list in extension.neon, as it is not defined by WordPress (see this GitHub search), but rather by WP-CLI.

Including WP_CLI in the dynamicConstantNames list prevents PHPStan from reporting the following code:

if (WP_CLI) {
    // do something
}

If WP_CLI is not defined, this will trigger a fatal error in PHP 8+.

Those using WP-CLI can easily add the WP_CLI constant to their own configuration. Therefore, this package should not prevent PHPStan from reporting potential fatal errors for some users.

Related #287

[szepeviktor]

@IanDelMar Thank you.

Have you ever seen if (WP_CLI)?

[IanDelMar]

No, I have not. It is just an example. Any fetch will result in the aforementioned fatal error if WP_CLI is not defined and not guarded by defined(). We should not instruct PHPStan to ignore cases it is intended to detect.

[szepeviktor]

I would leave it as is.